“A cookbook is only as good as its poorest/worst recipe” is a saying that has been printed on many images. Television chef and author Julia Child (1912-2004) said it several times, in slightly different ways.
       
“My feeling is that book is only as good as its worst recipe, and if you carefully follow the recipe and it doesn’t work out, it’s the book’s fault, not yours” was printed in Newsday (Long Island, NY) on April 1, 1979. “A cookbook is only as good as its worst recipe” was printed in the Richmond (VA) Times-Dispatch on November 13, 1991.
     
“A cookbook is only as good as its poorest recipe” was printed in the New York (NY) Times on October 8, 1997.
   
 
Wikiquote: Julia Child 
Julia Child (August 15, 1912 - August 13, 2004), television chef and author.
 
Quotes
. A cookbook is only as good as its worst recipe.
. Quoted in New York Times obituary
       
1 April 1979, Newsday (Long Island, NY), “Julia Child: ‘My Work Is My Hobby’: The LI Interview” by Janice Berman Alexander., pg. LI38, col. 2:
My feeling is that book is only as good as its worst recipe, and if you carefully follow the recipe and it doesn’t work out, it’s the book’s fault, not yours.
 
13 November 1991, Richmond (VA) Times-Dispatch, “Genuine Julia” by Louis Mahoney, pg. F-1:
“A cookbook is only as good as its worst recipe.”
 
Newspapers.com (Reprint in another newspaper.—ed.)
8 October 1997, New York (NY) Times, “Light’s Still on Julia Child, as Her Soul Mate Wanted” by Frank J. Prial, pg. F3, col. 5:
“A cookbook is only as good as its poorest recipe.”
 
Google Groups: alt.rasap
Old Lady’s Wisdom
christopher & joaquin
4/29/01
Julia Child Chef, 87, Santa Barbara, California
Interviewed by Mike Sager (Esquire Mag)
Photo Illustration by Roberto Parada
June 2000, Volume 133, Issue 6
(...)
A cookbook is only as good as its poorest recipe.
 
Google Groups: alt.obituaries
Julia Child; NY Times obit
Hyfler/Rosner
8/13/04
August 13, 2004
Julia Child, 91, Dies; She Entertained as She Taught Cooking
By REGINA SCHRAMBLING NY Times
(...)
When she wrote recipes, they were long and detailed because, she said, she felt obligated to insure their success. “A cookbook is only as good as its worst recipe,” she said.
 
Twitter
Good Life
@lifeandlearn
RT @wsombat: A cookbook is only as good as its worst recipe—Julia Child
1:55 AM · Jan 6, 2010·Twitter Web Client
 
Twitter
Dan Oshinsky
@danoshinsky
#AMinspiration from Miss Julia Child: “A cookbook is only as good as its poorest recipe.” http://bit.ly/avIwEI
10:06 AM · May 18, 2010·Twitter Web Client
 
Entrepreneur
17 Inspirational Quotes From Master Chef Julia Child
Lydia Belanger
August 15, 2016
(...)
On quality
“A cookbook is only as good as its poorest recipe.”
 
Google Books 
Title A Cookbook Is Only As Good As It’s Poorest Recipe: All Purpose 6x9 Blank Lined Notebook Journal Way Better Than a Card Trendy Unique Gift Marble White Pink Cooking
Author Chloe Mitchell Jp
Publisher Independently Published, 2019
ISBN 1694189899, 9781694189899
Length 120 pagei